To clarify, by this I meant that technically the exact speed limit
could be enforced once it is set (even though based on the 85th percentile). However, my other point is that I think as a society (including legal system) we sometimes/often don’t intend it to be interpreted an absolute/exact max limit. This may be (partly) based on the very nature of how we determine the speed limit - i.e. the 85th percentile.
A very clear example of the speed limit not intended as black and white is a Montana law that allows drivers to temporarily exceed the posted speed limit by 10mph in order to pass:
nhtsa.dot.gov/people/injury/enforce/speedlaws501/toc/mtspeed.pdf
“2. When traveling on a two lane road, a person may exceed this speed limit by 10 MPH in order to overtake and pass another vehicle.”
I think the main purpose of the speed limit is the common good including safety. As long as we drive safely and don’t use excessive speed I think we are following the spirit of the law even if we are driving at a speed that is over the posted speed limit by reasonable amounts.
What constitutes reasonable vs. excessive? Here are examples. I think it is clear that when someone is doing 45mph in a 35mph zone in midday on a busy street when many children are playing near the street that the person is speeding and not usng caution. On a straight stretch of the same street at 3am with no cars parked alongside and clear visibility etc.I don’t consider 40mph to be wrong provided all safety factors are considered.
We have a street where the speed limit is 25 then opens to 35 past farm land for about 1/3 mile. When I come out of the 25, I accelerate to maybe about 45 then begin slowing down for the stop at the intersection so I am exceeding the speed limit by a fairly large amount but not for a long time. The road is clear and there is open farm land on either side.
I think there are many cases in day to day driving where there are streteches of road where people accelerate a bit more and other strectches where they drive more slowly. The speed limit is not posted at every spot and some stretches of a road may be safer to go a bit faster. I don’t think we want to be a legalistic/pharisaic society. The public and police probably know of such stretches of road where the speed limit is more often reasonably exceeded. Some police in their off-duty with family might also exceed the speed on such stretches. At the same time we know when there is a crowded residential area or playground where you should be driving closely to (or below) the speed limit and using caution.
Sometimes, it may be prudent to go ***below ***the speed limit. There are reverse examples of the legalistic approach. On an ice covered street with children playing outside, going around the corner at the exact speed could almost be certain to cause the car to slide off the road. So technically you are gioing the speed limit but are violating the spirit of the law.
I think there was a pope who indicated in matters of doubt - liberty and in all things - charity. For driving, I think charity primarily means safety.